Consider President Clinton's situation. He is very rich and powerful, and can afford to have any chef prepare him anything he wants. He is very close to his outspoken daughter who was vegetarian for decades. Yet it still took extremely serious health problems (emergency surgery for a collapsed vein after quadruple bypass), his daughter's wedding, a desire to live to see grandchildren, and personal friendship with several vegan doctors to get him to finally eat a more plant-based diet (but still including eggs and fish).

So yes, it is clear that the health argument has an impact on rich, powerful men with vegan daughters, personal chefs, vegan doctors, and nearly-fatal heart problems.

(2013 update -- the latest media coverage makes it clear that President Clinton eats eggs and/or fish once a week. This not only indicates you can't really be vegan, but causes more animals to die than someone who ate beef and dairy at every meal.)

While it is, of course, really great to hear pseudo-veganism discussed positively (especially given the absurd attacks floating around), let's not read more into this than is really there. Land animals are in deep trouble if significant changes in diets are going to be limited to rich guys with personal chefs, vegan daughters and doctors, and severe health problems.